The present invention relates to a compound.
In particular the present invention relates to a compound and to a pharmaceutical composition comprising the compound.
Evidence suggests that oestrogens are the major mitogens involved in promoting the growth of tumours in endocrine-dependent tissues, such as the breast and endometrium. Although plasma oestrogen concentrations are similar in women with or without breast cancer, breast tumour oestrone and oestradiol levels are significantly higher than in normal breast tissue or blood. In situ synthesis of oestrogen is thought to make an important contribution to the high levels of oestrogens in tumours and therefore specific inhibitors of oestrogen biosynthesis are of potential value for the treatment of endocrine-dependent tumours.
Over the past two decades, there has been considerable interest in the development of inhibitors of the aromatase pathway which converts the androgen precursor androstenedione to oestrone. However, there is now evidence that the oestrone sulphatase (E1-STS) pathway, i.e. the hydrolysis of oestrone sulphate to oestrone (E1S to E1), as opposed to the aromatase pathway, is the major source of oestrogen in breast tumours1.2 This theory is supported by a modest reduction of plasma oestrogen concentration in postmenopausal women with breast cancer treated by aromatase inhibitors, such as aminoglutethimide and 4hydroxyandrostenedione3,4 and also by the fact that plasma E1S concentration in these aromatase inhibitor-treated patients remains relatively high. The long half-life of E1S in blood (10-12 h) compared with the unconjugated oestrogens (20 min)5 and high levels of steroid sulphatase activity in liver and, normal and malignant breast tissues, also lend support to this theory6. PCT/GB92/01587 teaches novel steroid sulphatase inhibitors and pharmaceutical compositions containing them for use in the treatment of oestrone dependent tumours, especially breast cancer. These steroid sulphatase inhibitors are sulphamate esters, such as N,N-dimethyl oestrone-3-sulphamate and, preferably, oestrone-3-sulphamate (otherwise known as xe2x80x9cEMATExe2x80x9d).
Some of the compounds disclosed in PCT/GB92/01587 are shown in FIG. 1.
It is known that EMATE is a potent E1-STS inhibitor as it displays more than 99% inhibition of E1-STS activity in intact MCF-7 cells at 0.1 mM. EMATE also inhibits the E1-STS enzyme in a time- and concentration-dependent manner, indicating that it acts as an active site-directed inactivator7,8. Although EMATE was originally designed for the inhibition of E1-STS, it also inhibits dehydroepiandrosterone sulphatase (DHA-STS), which is an enzyme that is believed to have a pivotal role in regulating the biosynthesis of the oestrogenic steroid androstenediol8,9. Also, there is now evidence to suggest that androstenediol may be of even greater importance as a promoter of breast tumour growth10. EMATE is also active in vivo as almost complete inhibition of rat liver E1-STS (99%) and DHA-STS (99%) activities resulted when it is administered either orally or subcutaneously11. In addition, EMATE has been shown to have a memory enhancing effect in rats14. Studies in mice have suggested an association between DHA-STS activity and the regulation of part of the immune response. It is thought that this may also occur in humans15.16. The bridging O-atom of the sulphamate moiety in EMATE is important for inhibitory activity. Thus, when the 3-O-atom is replaced by other heteroatoms (FIG. 1) as in oestrone-3-N-sulphamate (4) and oestrone-3-S-sulphamate (5), these analogues are weaker non-time-dependent inactivators12.
Although optimal potency for inhibition of E1-STS may have been attained in EMATE, it is possible that oestrone may be released during sulphatase inhibition8,12, and that EMATE and its oestradiol congener may possess oestrogenic activity13.
The present invention seeks to provide novel compounds suitable for the inhibition of E1-STS but preferably wherein those compounds have no, or a minimal, oestrogenic effect.
According to a first aspect of the present invention there is provided a sulphanate compound suitable for use as an inhibitor of oestrone sulphatase, wherein the compound has the Formula I; wherein A is a first group; B is an aryl ring structure having at least 4 carbon atoms in the ring and wherein the ring B is substituted in at least the 2 position and/or the 4 position with an atom or group other than H; X is a sulphamate group; wherein group A and ring B together are capable of mimicking the A and B rings of oestrone; and wherein group A is attached to at least one carbon atom in ring B.
The term xe2x80x9cmimicxe2x80x9d as used herein means having a similar or different structure but having a similar functional effect. In otherwords, group A and ring B together of the compounds of the present invention are bio-isosteres of the A and B rings of oestrone.
A key advantage of the present invention is that the sulphamate compounds of the present invention can act as EL-STS inhibitors.
Another advantage of the compounds of the present invention is that they may be potent in vivo and that they may have less oestrogenic activity than the known compounds and can therefore be deemed to be a xe2x80x9cnon-oestrogenic compoundxe2x80x9d. The term xe2x80x9cnon-oestrogenic compoundxe2x80x9d as used herein means a compound exhibiting no or substantially no oestrogenic activity.
The present invention therefore provides sulphamate compounds which may have a reduced oestrogenic activity.
Another advantage is that the compounds may not be capable of being metabolised to compounds which display or induce hormonal activity.
The compounds of the present invention are also advantageous in that they may be orally active.
The compounds of the present invention are further advantageous in that they may have an irreversible effect.
In a preferred embodiment, the-sulphamate compounds of the present invention are useful for the treatment of breast cancer.
In addition, the sulphamate compounds of the present invention are useful for the treatment of non-malignant conditions, such as the prevention of auto-immune diseases, particularly when pharmaceuticals may need to be administered from an early age.
The sulphamate compounds of the present invention are also believed to have therapeutic uses other than for the treatment of endocrine-dependent cancers, such as the treatment of autoimmune diseases.
Preferably, the sulphamate group is at position 3 of the ring B.
Preferably, the ring B has six carbon atoms in the ring.
Preferably, the compound has the Formula II; wherein X is the sulphamate group; A is the first group; R1 and/or R2 is a substituent other than H; wherein R1 and R2 may be the same or different but not both being H; and wherein optionally group A is attached to at least one other carbon atom in ring B.
Preferably, group A is additionally attached to the carbon atom at position 1 of the ring B.
Preferably, group A and ring B are a steroid ring structure or a substituted derivative thereof.
Preferably, the compound has the Formula IV; wherein X is the sulphamate group; R1 and/or R2 is a substituent other than H; wherein R1 and R2 may be the same or different but not both being H; and wherein Y is a suitable linking group.
Suitable linking groups for Y include groups made up of at least any one or more of C, O, N, and S. The linking groups can also comprise H. The linking group may also increase the size of the ring (i.e. the D ring). Preferably, however, the D ring comprising Y is a five-membered ring.
Preferably, Y is xe2x80x94CH2xe2x80x94 or xe2x80x94C(O)xe2x80x94.
Preferably, Y is xe2x80x94C(O)xe2x80x94.
Preferably, the compound has the Formula V; wherein X is the sulphamate group; R1 and/or R2 is a substituent other than H; and wherein R1 and R2 may be the same or different but not both being H.
The term xe2x80x9csulphamatexe2x80x9d as used herein includes an ester of sulphamic acid, or an ester of an N-substituted derivative of sulphamic acid, or a salt thereof.
Preferably, the sulphamate group has the Formula III.
In Formula III, each of R3 and R4 is independently selected from H or a hydrocarbyl group.
The term xe2x80x9chydrocarbyl groupxe2x80x9d as used herein means a group comprising at least C and H and may optionally comprise one or more other suitable substituents. Examples of such substituents may include halo-, alkoxy-, nitro-, an alkyl group, a cyclic group etc. In addition to the possibility of the substituents being a cyclic group, a combination of substituents may form a cyclic group. If the hydrocarbyl group comprises more than one C then those carbons need not necessarily be linked to each other. For example, at least two of the carbons may be linked via a suitable element or group. Thus, the hydrocarbyl group may contain hetero atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for instance, sulphur, nitrogen and oxygen. A non-limiting example of a hydrocarbyl group is an acyl group.
In one preferred embodiment of the present invention, the hydrocarbyl group for the sulphamate group is a hydrocarbon group.
Here the term xe2x80x9chydrocarbonxe2x80x9d means any one of an alkyl group, an alkenyl group, an alkynyl group, which groups may be linear, branched or cyclic, or an aryl group. The term hydrocarbon also includes those groups but wherein they have been optionally substituted. If the hydrocarbon is a branched structure having substituent(s) thereon, then the substitution may be on either the hydrocarbon backbone or on the branch; alternatively the substitutions may be on the hydrocarbon backbone and on the branch.
Preferably, R3 and R4 are independently selected from H or alkyl, cycloalkyl, alkenyl and aryl, or together represent alkylene, wherein the or each alkyl or cycloalkyl or alkenyl or optionally contain one or more hetero atoms or groups.
When substituted, the N-substituted compounds of this invention may contain one or two N-alkyl, N-alkenyl, N-cycloalkyl or N-aryl substituents, preferably containing or each containing a maximum of 10 carbon atoms. When R3 and/or R4 is alkyl, the preferred On values are those where R3 and R4 are each independently selected from lower alkyl groups containing from 1 to 5 carbon atoms, that is to say methyl, ethyl, propyl etc. Preferably R3 and R4 are both methyl. When R3 and/or R4 is aryl, typical values are phenyl and tolyl (xe2x80x94PhCH3; o-, m- or p-). Where R3 and R4 represent cycloalkyl, typical values are cyclopropyl, cyclopentyl, cyclohexyl etc. When joined together R3 and R4 typically represent an alkylene group providing a chain of 4 to 6 carbon atoms, optionally interrupted by one or more hetero atoms or groups, e.g. (xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94 to provide a 5-, 6- or 7-membered heterocycle, e.g. morpholino, pyrrolidino or piperidino.
Within the values alkyl, cycloalkyl, alkenyl and aryl we include substituted groups containing as substituents therein one or more groups which do not interfere with the sulphatase inhibitory activity of the compound in question. Exemplary non-interfering substituents include hydroxy, amino, halo, alkoxy, alkyl and aryl.
In some preferred embodiments, at least one of R3 and R4 is H.
In some further preferred embodiments, each of R3 and R4 is H.
Preferably, each of R1 and R2 is independently selected from H, l, cycloalkyl, alkenyl, aryl, substituted alkyl, substituted cycloalkyl, substituted alkenyl, substituted aryl, any other suitable hydrocarbyl group, a nitrogen containing group, a S containing group, a carboxy containing group.
Likewise, here, the term xe2x80x9chydrocarbyl groupxe2x80x9d means a group comprising at least C and H and may optionally comprise one or more other suitable substituents. Examples of such substituents may include halo-, alkoxy-, nitro-, an alkyl group, a cyclic group etc. In addition to the possibility of the substituents being a cyclic group, a combination of substituents may form a cyclic group. If the hydrocarbyl group comprises more than one C then those carbons need not necessarily be linked to each other. For example, at least two of the carbons may be linked via a suitable element or group. Thus, the hydrocarbyl group may contain hetero atoms. Suitable hetero atoms will be apparent to those skilled in the art and include, for instance, sulphur, nitrogen and oxygen. A non-limiting example of a hydrocarbyl group is an acyl group.
Preferably, each of R1 and R2 is independently selected from H, C1-6 alkyl, C1-6 cycloalkyl, C1-6 alkenyl, substituted C1-6 alkyl, substituted C1-6 cycloalkyl, substituted C1-6 alkenyl, substituted aryl, a nitrogen containing group, a S containing group, or a carboxy group having from 1-6 carbon atoms.
Likewise, here within the values alkyl, cycloalkyl, alkenyl and aryl we include substituted groups containing as substituents therein one or more groups which do not interfere with the sulphatase inhibitory activity of the compound in question. Exemplary non-interfering substituents include hydroxy, amino, halo, alkoxy, alkyl and aryl.
Preferably, each of R1 and R2 is independently selected from H, C1-6 alkyl, C1-6 alkenyl, a nitrogen containing group, or a carboxy group having from 1-6 carbon atoms.
Preferably, each of R1 and R2 is independently selected from H, C1-6 alkyl C1-6 alkenyl, NO2, or a carboxy group having from 1-6 carbon atoms.
Preferably, each of R1 and R2 is independently selected from H, C3 alkyl, C3 alkenyl, NO2, or H3CO.
Preferably, the compound is any one of the Formulae V-IX.
Preferably, for some applications, the compound is further characterised by the feature that if the sulphamate group were to be substituted by a sulphate group to form a sulphate derivative, then the sulphate derivative would be hydrolysable by an enzyme having steroid sulphatase (E.C. 3.1.6.2) activityxe2x80x94i.e. when incubated with steroid sulphatase EC 3.1.6.2 at pH 7.4 and 37xc2x0 C.
In one preferred embodiment, if the sulphamate group of the compound were to be replaced with a sulphate group to form a sulphate compound then that sulphate compound would be hydrolysable by an enzyme having steroid sulphatase (E.C. 3.1.6.2) activity and would yield a K, value of less than 50 xcexcmmolar when incubated with steroid sulphatase EC 3.1.6.2 at pH 7.4 and 37xc2x0 C.
In another preferred embodiment, if the sulphamate group of the compound were to be replaced with a sulphate group to form a sulphate compound then that sulphate compound would be hydrolysable by an enzyme having steroid sulphatase (E.C. 3.1.6.2) activity and would yield a Km value of less than 50 xcexcmolar when incubated with steroid sulphatase EC 3.1.6.2 at pH 7.4 and 37xc2x0 C.
In a highly preferred embodiment, the compound of the present invention is not hydrolysable by an enzyme having steroid sulphatase (E.C. 3.1.6.2) activity.
Thus, the present invention provides novel sulphamate compounds.
Preferably the group A and the ring B togetherxe2x80x94hereinafter referred to as xe2x80x9cgroup A/ring B combinationxe2x80x9dxe2x80x94will contain, inclusive of all substituents, a maximum of about 50 carbon atoms, more usually no more than about 30 to 40 carbon atoms.
A preferred group A/ring B combination has a steroidal ring structure, that is to say a cyclopentanophenanthrene skeleton. Preferably, the sulphamyl or substituted sulphamyl group is attached to that skeleton in the 3-position.
Thus, according to a preferred embodiment, the group A/ring B combination is a substituted or unsubstituted, saturated or unsaturated steroid nucleus.
A suitable steroid nucleus is a substituted (i.e. substituted in at least the 2 and/or 4 position and optionally elsewhere in the steroid nucleus) derivative of any one of: oestrone, 2-OH-oestrone, 2-methoxy-oestrone, 4-OH-oestrone, 6a-OH-oestrone, 7a-OH-oestrone, 16a-OH-oestrone, 16b-OH-oestrone, oestradiol, 2-OH-17b-oestradiol, 2-methoxy-17b-oestradiol, 4-OH-17b-oestradiol, 6a-OH-17b-oestradiol, 7a-OH-17b-oestradiol, 16a-OH-17a-oestradiol, 16b-OH-17a-oestradiol, 16b-OH-17b-stradiol, 17a-oestradiol, 17b-oestradiol, 17a-ethinyl-17b-oestradiol, oestriol, 2xe2x80x94OH-oestriol, 2-methoxy-oestriol, 4-OH-oestriol, 6a-OH-oestriol, 7a-OH-oestriol, dehydroepiandrosterone, 6a-OH-dehydroepiandrosterone, 7a-OH-dehydroepiandrosterone, 16a-OH-dehydroepiandrosterone, 16b-OH-dehydroepiandrosterone.
In general terms the group A/ring B combination may contain a variety of non-interfering substituents. In particular, the group A/ring B combination may contain one or more hydroxy, alkyl especially lower (C1-C6) alkyl, e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl and other pentyl isomers, and n-hexyl and other hexyl isomers, alkoxy especially lower (C1-C6) alkoxy, e.g. methoxy, ethoxy, propoxy etc., alkenyl, e.g. ethenyl, or halogen, e.g. fluoro substituents.
The group A/ring B combination may even be a non-steroidal ring system.
A suitable non-steroidal ring system is a substituted (i.e. substituted in at least the 2 and/or 4 position and optionally elsewhere in the ring system) derivative of any one of: diethylstilboestrot, stilboestrol.
When substituted, the N-substituted compounds of this invention may contain one or two N-alkyl, N-alkenyl, N-cycloalkyl or N-aryl substituents, preferably containing or each containing a maximum of 10 carbon atoms.
When R1 and/or R2 and/or R3 and/or R4 is alkyl, the preferred values are those where each of R1 and R2 and R3 and R4 is independently selected from lower alkyl groups containing from 1 to 6 carbon atoms, that is to say methyl, ethyl, propyl etc.
When R1 and/or R2 and/or R3 and/or R4 is aryl, typical groups are phenyl and tolyl (xe2x80x94PhCH3; o-, m- or p-).
Where R1 and/or R2 and/or R3 and/or R4 represent cycloalkyl, typical values are cyclopropyl, cyclopentyl, cyctohexyl etc.
When joined together R3 and R4 typically represent an alkylene group providing a chain of 4 to 6 carbon atoms, optionally interrupted by one or more hetero atoms or groups, e.g. xe2x80x94Oxe2x80x94 or xe2x80x94NHxe2x80x94 to provide a 5-, 6- or 7-membered heterocycle, e.g. morpholino, pyrrolidino or piperidino.
Within the values alkyl, cycloalkyl, alkenyl and aryl we include substituted groups containing as substituents therein one or more groups which do not interfere with the sulphatase inhibitory activity of the compound in question. Examples of non-interfering substituents include hydroxy, amino, halo, alkoxy, alkyl and aryl.
We have also surprisingly found that when the compound has the Formula IV where Y=xe2x80x94CH2xe2x80x94 it is not necessary for the compound to be substituted in the 2 and 4 ring positions, ie R1 and R2 may both be hydrogen. In one embodiment of this aspect, any of the ring positions (including R1 and R2, but excluding Y) may be substituted.
Thus, according to another aspect of the present invention there is provided a sulphamate compound suitable for use as an inhibitor of oestrone sulphatase wherein the compound has the Formula X and wherein X is a sulphamate group, and Y is CH2 and optionally any other H attached directly to the ring system is substituted by another group.
X may be as described above.
Any replacement for H on the ring system may be any one of the substituents described above in relation to R1 and R2.
In an especially preferred embodiment there is no substitution on the ring system, ie a compound of Formula IV where Y is xe2x80x94CH2xe2x80x94 and R1 and R2 are both H.
According to a second aspect of the present invention there is provided a sulphamate compound according to the present invention for use as a pharmaceutical.
According to a third aspect of the present invention there is provided a sulphamate compound according to the present invention for inhibiting oestrone sulphatase.
According to a fourth aspect of the present invention there is provided a pharmaceutical composition comprising a sulphamate compound according to the present invention; and a pharmaceutically acceptable carrier, excipient, adjuvant or diluent.
According to a fifth aspect of the present invention there is provided the use of a sulphamate compound according to the present invention in the manufacture of a pharmaceutical for inhibiting oestrone sulphatase.
The sulphamate compounds of the present invention may be prepared by reacting an appropriate alcohol with a sulfamoyl chloride, R3R4NSO2Cl.
Preferred conditions for carrying out the reaction are as follows.
Sodium hydride and a sulfamoyl chloride are added to a stirred solution of the alcohol in anhydrous dimethyl formamide at 0xc2x0 C. Subsequently, the reaction is allowed to warm to room temperature whereupon stirring is continued for a further 24 hours. The reaction mixture is poured onto a cold saturated solution of sodium bicarbonate and the resulting aqueous phase is extracted with dichloromethane. The combined organic extracts are dried over anhydrous MgSO4. Filtration followed by solvent evaporation in vacuo and co-evaporated with toluene affords a crude residue which is further purified by flash chromatography.
Preferably, the alcohol is derivatised, as appropriate, prior to reaction with the sulfamoyl chloride. Where necessary, functional groups in the alcohol may be protected in known manner and the protecting group or groups removed at the end of the reaction.
For pharmaceutical administration, the steroid sulphatase inhibitors of this invention can be formulated in any suitable manner utilising conventional pharmaceutical formulating techniques and pharmaceutical carriers, adjuvants, excipients, diluents etc. and usually for parenteral administration. Approximate effective dose rates are in the range 100 to 800 mg/day depending on the individual activities of the compounds in question and for a patient of average (70 Kg) bodyweight. More usual dosage rates for the preferred and more active compounds will be in the range 200 to 800 mg/day, more preferably, 200 to 500 mg/day, most preferably from 200 to 250 mg/day. They may be given in single dose regimes, split dose regimes and/or in multiple dose regimes lasting over several days. For oral administration they may be formulated in tablets, capsules, solution or suspension containing from 100 to 500 mg of compound per unit dose. Alternatively and preferably the compounds will be formulated for parenteral administration in a suitable parenterally administrable carrier and providing single daily dosage rates in the range 200 to 800 mg, preferably 200 to 500, more preferably 200 to 250 mg. Such effective daily doses will, however, vary depending on inherent activity of the active ingredient and on the bodyweight of the patient, such variations being within the skill and judgement of the physician.
For particular applications, it is envisaged that the steroid sulphatase inhibitors of this invention may be used in combination therapies, either with another sulphatase inhibitor, or, for example, in combination with an aromatase inhibitor, such as for example, 4-hydroxyandrostenedione (4-OHA).
In summation, the present invention provides novel compounds for use as steroid sulphatase inhibitors, and pharmaceutical compositions containing them.